HUMAN EXPANSION INTO SPACE

Q. Will humans expand into space?

A. Yes. I am disappointed that the Apollo Project was not followed up with a start on colonization.

The Orion Project might have provided nuclear rockets that would have made colonization relatively inexpensive. Now NASA is thinking about nuclear powered ion rockets. These should make interplanetary journeys take a tenth as long as when chemical rockets are used.

Alas, NASA has taken over the name Orion for a chemical rocket system based on 1960s technology. Cute of them.

A. Interplanetary space, the moon and asteroids seem the most feasible.

Q. Isn't space essential for human survival for power satellites, material from space or relieving excess population?

A. No, it isn't necessary for any of these - at least for the next billion years. There are plenty of resources on earth for its expected future population. Space enthusiasts, who rely on arguments that space resources are necessary for mere human survival are doomed to disappointment for the forseeable future. There will continue to be good arguments that other solutions are cheaper.

The valid survival argument for space is to disperse human population, because of the possibility of a really bad asteroid strike or a really bad nuclear war.

A. Yes.

Q. Why will people do it?

A. There are two possibilities. The first is that it will be done for the usual motivations of exploration, curiosity and adventure. The second reason why some groups of people will do it is to get away from the rest of us.

Q. What are the advantages of living in space?

A. There are a number of advantages.

• The lack of gravity should be fun. At least the astronauts have found it fun.

• There may be lots of room. Consider a skin tight space suit. Suppose that one lived in this space suit and spent one's time in the space suit in an enormous apartment with all kinds of facilities. The only rub is that the apartment is in vacuum. Would a person feel cramped because of the space suit or would he feel that the enormous apartment was a luxury? I doubt we can know until some people try it. Obviously, the design of the space suit will be critical.

  If all space occupied by humans has to be pressurized, there will be less space. However, the mass of the air in the space will far exceed the mass of the wall required to contain it.

• It seems that astronauts usually have considerable difficulty in rebuilding their muscles after return to earth from a space mission of any length. Inhabitants of space may have to permanently commit themselves to living there.

• Since the 1940s there has been science fiction about people with weak muscles living in space. I believe the most famous story is the 1942 Waldo by Robert Heinlein. Elderly people like me in 2004 might like it a lot, and I suspect that I would like it even better later. In 1998 former astronaut and former Senator John Glenn made a Shuttle trip at the age of 77, one purpose of which was to see how elderly people would adapt to space. Unfortunately, from the scientific point of view, Senator Glenn undertook extensive new training for his Shuttle trip. My fantasy was that the Senator should have been Strom Thurmond who was in his 90s and quite feeble. It would have been really interesting if Thurmond got up there ok and then enjoyed being able to get around in weightless conditions. If the experiment had been done without training but with a companion to avoid troubles, it would have been maximally informative. However, that's not NASA's style.

• Large structures in space, on asteroids, or even on the moon or Mars will be much more feasible than on earth, because in space they won't have to hold up their own mass, and in these low gravity places much less of the mass will go into structure.

Here's a fantasy about a human space based independent colony. They construct a model of the galaxy with all 10^(11) stars. If the model stars were a foot apart a cubical galaxy would be less than two miles on a side. Since the galaxy is not cubical, the space taken will be much more, say a light year per foot. The model is for children and others to play in. There's no gravity, so the children can fly themselves out on the spiral arms or into the core. A robot disreetly follows each visitor supplying food and removing wastes. A visitor can fall asleep whenever he wants to. Children brought up in space will find that easy, but visitors from earth may need something to cling to. [More to come.]

Q. What about interstellar travel and colonization?

A. With technology based on present science, multi-generation voyages will be required. Still, human society on earth can last for billions of years. Surely, the multi-generation voyages taking mere thousands of years will be undertaken in all that time. If human longevity is increased enough, 10,000 year journeys may be undertaken with the lifetime of the crew. Also if speeds close to the velocity of light can be achieved, the subjective time of the travellers for a journey will be less than that of the stay-at-homes in the ratio sqrt(1 - (v^2/c^2)). Poul Anderson wrote some nice science fiction novels about this. He took a rather gloomy view of humans maintaining their motivation for interstellar colonization.

Q. What about contact with other civilizations?

We should keep trying. However, the SETI (Search for extra-terrestrial intelligence) projects are relying on radio. It seems to me quite probable that civilizations whose technology is thousands or millions of years in advance of our own will use different means of communication than what can be invented a mere 100 years after the invention of radio. I admit I don't have any other definite technology to propose, although I'm working on a science fiction story in which beams of neutrinos are used.

When radio sources pulsating in the milliseconds were discovered, the LGM (little green men) theory was briefly entertained. Alas, they were just rapidly spinning neutron stars. I'm sure the LGM theory will be revived and considered if the astronomers discover any phenomena admitting that interpretation.

Send comments to mccarthy@stanford.edu. I sometimes make changes suggested in them. - John McCarthy